Members of the Academie française meet at the Institut de France in Paris to discuss the French language. The body has elected its first British-born member, the poet Michael Edwards. Photograph: Lionel Cironneau/AP

A poet, critic and literature professor from Barnes in southwest London has become the first British-born writer to be elected to the elite Académie française, France's highest learned body charged with defending the purity of the French language.

Michael Edwards, 74, was voted into the exclusive group known as "The Immortals" on his third attempt, and will now take a seat among up to 40 members in their gold-braided uniforms under the gilded dome of the Institut de France. A commission chosen from among them advises on what new words should be entered into the French dictionary, studiously defending French against foreign impurities, notably those from English.

Edwards, a poet, translator, and literary critic specialising in French language and literature, was born in Barnes and first discovered French aged 11 at Kingston Grammar School in Surrey. Married to a French wife, he has dual British and French nationality, and is acclaimed for his writing in both French and English – often shifting between the two in the same work or poem. He formerly held the chairs of French and English at the University of Warwick, but also held the first joint chair in poetry and English literature at Paris's prestigious College de France. He has written on Shakespeare, Molière and Racine and Rimbaud.

Edwards told the Guardian: "French is not just another language, it's another way of understanding the world, a way of being, of sensing emotion." He said the French had "an intimacy with their language" which English people did not necessarily have. They also felt they were being "invaded" by English – "a kind of Anglo-American small talk which isn't really elegant English at all" – as well as the pressure for intellectuals to write in English language publications. Asked what role he would play in defending French, he said: "The French talk of the purity of their language and they are right. On the other hand, languages do change and they thrive by change, and they thrive very often by a kind of impurity. Elizabethan English changed and became immensely rich by borrowing from other languages and by inventing words continuously. The French do like to purify. But there was a letter to the Académie française by Fénelon in 1714 in which he said we have purified the language, we have also impoverished it a bit and it would be a good idea now to enrich it. That's the sort of message I would like to bring, with the humility of being just one person."

The Académie française was founded in the 17th century by Cardinal Richelieu to keep watch over the French language and has included writers, philosophers, politicians and military figures. There is no rule that members must be born in France. Several current members were born outside France, including the Lebanese-born writer Amin Maalouf and Chinese-born writer François Cheng. But Edwards is the first British-born writer and academic to be elected.

In the vote this week, Edwards beat Jean-Noël Jeanneney, a former minister and president of Radio France.

In Le Figaro, Christophe Carlier, who has written on the Académie française, said Edwards appointment "would allow the Académie to come out of the anti-Franglais posture" to which he said it was too often accused of being confined.